Personally, I wouldn't base my decision on purchasing a housing on how many dives you have. Regardless of the size difference between the Canon and Ikelite housings, either housing will give you one additional "chore" to deal with while diving. My point being, the Canon being a bit smaller than the Ikelite won't make this "chore" easier for you. What you need to consider is the buoyancy of the housing (again, if overburdening yourself is your main concern). Remember, you are new and still working on your own buoyancy issues. If you bring a housing down with you that housing's buoyancy is going to affect you more than the size of the housing. I'm not certain but I believe Ikelite housings are billed as being neutrally bouyant, and Canon is a bit positive. Someone help me (and the OP) out here. Am I correct on the buoyancy of these two housings?
In any case, Cerge, its' buoyancy not size that should be your first concern. Your second concern is this: how much did you pay for your Canon G9? I paid $500 for mine. Are you comfortable protecting it with a $200 housing (Canon) or the Ikelite? I'm not knocking Canon housings, just putting the question out there.
Just my opinions, but based on the fact that I have a Canon G9 and have been agonizing over which housing to get, as well as which strobe. Personally, I have to go with Ikelite for two main reasons. Ikelite costs more because it's got a proven record for keeping cameras dry and because I want to go ttl with the strobe instead of using a fiber optic.
So I guess besides buoyancy and camera protection, yourthird consideration is: what do I want to do when acquiring a strobe? If you want ttl, you will have to get the Ikelite.